Originally posted by ManuH AFAIK they were not bought by Hoya, they merged with Hoya. Not the same thing even if Hoya is the bigger company.
I don't remember the exact dates, but Hoya made a public offer to buy outstanding stock in Pentax Corporation. They successfully purchased controlling interest in the company. I'm not sure exactly what percentage they ended up buying, but it was a lot more than fifty percent.
There was a period of time, during which Pentax Corporation continued to exist, but just about all of the stock was owned by Hoya. The two corporations were, at that point, seperate legal entities.
Just before the K20D was released, Hoya merged the Pentax Corporation into Hoya corporation. At that point, the Pentax Corp. ceased to exist, but for maybe six months, it had existed as a wholly-owned subsidiary of Hoya. Since Hoya owned almost all of the stock in Pentax Corp., they had no choice in the matter. At that point, Hoya exchanged Hoya stock for Pentax stock. Any remaining holdouts, who had not sold their Pentax shares to Hoya, were involuntarily transformed into Hoya shareholders.
I remember that it was before the K20D because, when the K20D came out, there were many complaints that Hoya had broken some third-party software by changing the PEF format. I believe that Apple's iPhoto was the most prominent software thus affected. It turns out that Hoya/Pentax hadn't changed the PEF format, at all. They had merely updated the manufacturer name in the EXIF data to reflect simply "Pentax", while the predecessor K10D's EXIF shows Pentax Corporation, which no longer existed. Apparently, iPhoto used the EXIF data to identify the raw file format.
Today, Pentax is only a brand name owned by Hoya, and a division within the Hoya Corporation.
At the time, some thought that the merger spelled the death knell for Pentax cameras. I felt, and still feel, that, if Hoya had merely wanted the medical imaging business and not the camera business, it would have been easier for them to sell Pentax by keeping it as a seperate corporation. In that case, selling Pentax would only have required a simple stock transfer. As it is now, extracting Pentax from Hoya would be much more difficult.
As I recall, Pentax Corporation management was cool to the idea of being bought/merged with Hoya or anyone else. One of their largest stockholders, however, was pushing for it, so Hoya was able to stage a more-or-less hostile takeover. IIRC, a couple of top-level Pentax execs quit in protest.